JPH0224545A - Method for fluorescence x-ray analysis - Google Patents

Abstract

PURPOSE:To enable selection of an arbitrary element as an internal standard element by a method wherein a thin film containing an element to be used as an internal standard is provided on the measuring surface of a sample. CONSTITUTION:A number of samples 1 are set on a rotatable sample holder 2 and subjected to X-ray irradiation from an X-ray tube 3 at a prescribed position, and a fluorescence X-ray generated by this irradiation is detected by a detector 4. The sample 1 is formed in the shape of a column and the surface thereof is smoothed to be a measuring surface. On this measuring surface, a thin film 5 containing an element to be used as an internal standard is provided. In order to measure the content of an element to be inspected in the sample 1, first the thin film 5 is provided on the sample 1 and the fluorescence X-ray generated from the sample 1 is detected. Then the intensity of the fluorescence X-ray in the thin film 5 and the intensity of the fluorescence X-ray in the element to be inspected in the sample 1 are measured. By determining the ratio in the intensity between these X-rays therefore, the content of the element to be inspected can be quantified.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to not only lumpy and plate-like samples, but also crushed samples, cut samples,
The present invention relates to a fluorescent X-ray analysis method for quantifying elements contained in wire samples, powder samples, etc.

<Prior art> In a quantitative method using fluorescent X-ray analysis, for example, a standard sample with known element content is used to determine the relationship between the content and fluorescent X-ray intensity to create a calibration curve (sensitivity curve). By comparing this with the fluorescent X-ray intensity of the unknown sample, the element content in the unknown sample can be determined.

In this case, changes may occur in the measured values due to fluctuations in the power supply of the fluorescent X-ray analyzer, changes in the characteristics of each part of the equipment, etc., so compensation methods such as the internal standard method (internal standard method) are used to improve measurement accuracy. ing.

<Problem to be solved by the invention> However, in this internal standard method, the X-ray intensity of an appropriate standard element contained in the sample or a known amount of the standard element mixed in the sample and the test element are Since quantitative determination is based on the ratio of X-ray intensities, it may be difficult to select an appropriate standard element for the sample, or it may be complicated to mix the standard element into the sample. In some cases, it may be difficult to uniformly disperse standard elements.

In order to solve these conventional problems, the inventors of the present invention have conducted intensive studies and found that after smoothing the measurement surface of the sample by conventional operations such as surface polishing and squeezing of the sample, By placing a thin film containing an element to be used as an internal standard on this measurement surface, the inventors discovered that the element to be tested in the sample could be quantified with high accuracy by the internal standard method, and the present invention was completed.

Means for Solving the Problems and Their Effects> To be more specific, the characteristics of the present invention are as follows: A thin film containing an element to be used as an internal standard is placed on the measurement surface of the sample; The present invention is a fluorescent X-ray analysis method for quantifying elements contained in a sample by determining the fluorescent X-ray intensity ratio of an internal standard element in a thin film and a test element in a sample by irradiating X-rays.

That is, according to the present invention, the content of the test element can be measured with high accuracy by simply placing a pre-formed thin film on the surface of the sample without mixing the standard element throughout the sample.

<Example> Figure 1 shows a fluorescent X-ray analyzer system (either wavelength dispersive type or energy dispersive type) for carrying out the method of the present invention.
This is an example.

In this device system, a large number of samples 1... are placed on a rotatable sample holder 2, and at a predetermined position are exposed to X-rays from an X-ray tube 3, and fluorescent X-rays are generated by this irradiation. is detected by the detector 4. Here, in a wavelength-dispersive X-ray fluorescence analyzer system, the detector 4 consists of an XvA spectrometer that combines a spectroscopic crystal and a slit, and in an energy-dispersive X-ray fluorescence analyzer system, the detector 4 consists of a semiconductor detector. Consists of vessels.

Depending on the type of sample 1, if it is a solid sample,
For example, as shown in FIG. 2, it is formed into a cylindrical shape (in the case of pulverized or powdered samples, it is solidified), and its surface is smoothed by polishing, squeezing, etc., and used as a measurement surface. Then, a thin film 5 containing an element to be used as an internal standard is placed on this measurement surface.

For example, as shown in FIG. 3, this thin film 5 is coated with an internal standard element 7 (a compound containing the internal standard element 7) on a film 6 made of a resin such as polypropylene or polyethylene by vapor deposition or sputtering. (The same applies hereafter) or by mixing them into a resin. Further, as another method for forming the thin film 5, there is shown in FIG.
A) As shown in (B), a large number of small holes 9 . . . and slits 10 .
.

. . , or by layering an element to be used as an internal standard on this metal plate 8 by vapor deposition, sputtering, or the like.

Here, an element that is not contained in sample 1 is selected as the internal standard element.

In the thin film 5, if the layer thickness of the internal standard element 7 of the film 6 or the metal plate or the thickness of the internal standard element-containing film 6 and metal plate 8 are too thin, the X-ray intensity of the internal standard element obtained is becomes small, and conversely, if it is too thick, the irradiated X
Since the rays cannot reach the part of sample 1 under the membrane (inside), the fluorescent X-ray intensity of the internal standard element and the fluorescent X-ray intensity of the test element in sample 1 are selected to be appropriate values. Also,
The fluorescent X-ray intensity of the obtained internal standard element and the fluorescent X-ray intensity of the test element in the sample 1 are appropriate values even for the sizes of the small holes 9... and the slits 10... of the metal plate 8. shall be selected so that

As for the thin films 5 obtained in this way, it is advisable to prepare in advance several types of thin films with different internal standard elements, different stacked thicknesses of the internal standard elements 7, or different thicknesses of films or metal plates. .

To measure the content of the test element in the sample 1 using this thin film 5, first, the thin film 5 is placed on the sample 1, and in this state, an X-ray When the fluorescent X-rays generated from the sample 1 are detected, the fluorescent Xis intensity in the thin film 5 and the fluorescent X-ray intensity of the test element in the sample 1 are measured. By determining this, the content of the test element in the sample 1 can be quantified.

During this measurement, the sample 1 is irradiated with X-rays with an appropriate irradiation range (for example, the range shown by the dotted lines in FIGS. 4(A) and 4(B)!), and in particular, the small hole 9... In the case of a metal plate thin film 5 having slits 10, etc., it is preferable that the sample 1
It is preferable to rotate the detection data to make the detection data uniform.

In the above example, the sample 1 is cylindrical, but the present invention is not limited to this. Various shapes are possible depending on the shape of the sample 1, and at least a thin film is placed on the measurement surface. Any shape that can be used is fine.

<Effects of the Invention> As is clear from the above explanation, according to the fluorescent X-ray analysis method of the present invention, the following excellent effects can be obtained.

(2) Since an element contained in a thin film placed on the measurement surface of the sample is used as the internal standard, any element can be selected as the internal standard element. Therefore, even when it is not possible to select an appropriate element as an internal standard for the elements contained in a sample as in the past, the present invention makes it possible to use the internal standard method.

(2) In carrying out internal standardization, it is only necessary to place a thin film on the smooth measurement surface of the prepared sample, so the operation is extremely simple. Therefore, the complexity of mixing standard elements into the entire sample as in the conventional method can be avoided.

■Also, since the internal standard element for the thin film can be formed by vapor deposition or sputtering, or mixed into the resin film or metal plate that is the base of the thin film, it is easy to mold and control the film thickness. At the same time, the standard elements can be easily dispersed uniformly, and higher-precision analysis can be achieved than with conventional methods.

(2) Furthermore, if several types of thin films made of resin films or metal plates containing different internal standard elements are prepared in advance, it becomes possible to cover a wide measurement range.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of a fluorescent X-ray analyzer system for implementing the method of the present invention, Fig. 2 is a perspective view showing an example of a sample and thin film used in the present invention, and Fig. 3 4(A) and 4(B) are respective plan views showing the thin film on the other side. In the figure, 1... Sample, 2... Sample holder 3... X-ray tube, 4... Detector, 5... Thin film, 6... Film, 7... ...Element used as internal standard, 8..Metal plate, 9..Small hole, 10..Slit, Figure 1

Claims (1)

[Claims] A thin film containing an element to be used as an internal standard is placed on the measurement surface of the sample, and the fluorescent X-ray intensity ratio of the internal standard element in the thin film and the test element in the sample is determined by irradiation with A fluorescent X-ray analysis method characterized by quantifying elements contained in.